Functional assessment involves generating hypotheses about the purpose a behavior serves and the environmental variables maintaining it in order to develop effective and efficient interventions. Functional assessment has been used extensively with students with severe disabilities in special education settings. However, few applications of functional assessment have been reported with students with mild disabilities in general education classrooms. The purpose of this article is to address the use of functional assessment in general education classrooms with students with mild disabilities. We present the theoretical foundations of functional assessment, describe the procedures involved in conducting a functional assessment, discuss some of the obstacles to applying functional assessment in general education classrooms, and make recommendations for the future use of functional assessment in general education classrooms with students with mild disabilities.